The present invention relates to an improved high-pressure pump with filler plug.
It applies in particular to a high-pressure pump for supplying a motor vehicle internal combustion engine with fuel. In this case, the transferred liquid is fuel.
The state of the art already knows a high-pressure pump for pumping a first liquid, known as the transferred liquid, of the type comprising a main unit for pumping the transferred liquid, which unit is actuated by a secondary unit for pumping a second liquid, known as the working liquid, the secondary unit comprising means for filling a reservoir with working liquid which comprise a filling neck, connected to the reservoir, which can be plugged by a plug provided with a plugging surface intended to collaborate with a plugging seat formed in the neck.
A pump of this type is described for example in WO 97/47883.
It is an object of the invention to propose means for filling the reservoir with working liquid which allow this reservoir to be completely filled with liquid, these means moreover being simple and easy to plug.
To this end, the subject of the invention is a high-pressure pump of the aforementioned type, characterized in that the neck is adapted to contain an excess of working liquid overflowing from the reservoir, the overflow level extending into the neck above the seat, it being possible for the plug to move in the neck, in the presence of the overflow of working liquid, between a position of preplugging, in which the plugging surface is away from the seat, above this seat, and a position of plugging in which the plugging surface is in sealed contact with the seat.
According to other features of the invention:
the reservoir is connected to means for compensating for expansion of the working liquid, which means comprise a flexible diaphragm which can be deformed according to the variations in volume of the working liquid;
the plug comprises a more or less axial blind hole forming a receptacle for the overflow, communicating via a more or less radial drilling of the plug with a peripheral counterbore of the plug which is extended axially by the plugging surface, this counterbore being connected to the reservoir when the plug is in its preplugging position;
the plugging surface and the plugging seat have conical overall shapes, the plugging surface converging toward the plugging seat;
the plug can move by screwing between its preplugging and plugging positions;
the plug has a driving head through which the open end of the blind hole opens, the head being delimited by an exterior or interior polygonal driving surface;
the plug comprises a ball that can be moved by force between its preplugging and plugging positions, the surface of the ball forming the plugging surface of the plug; and
the transferred liquid is a fuel for a motor vehicle internal combustion engine.
The invention will be better understood from reading the description which will follow which is given solely by way of example and made with reference to the drawings in which: